نشریه بهره برداری و پرورش آبزیان
سال دهم شماره 3 (پاییز 1400)

The aim of this study was to investigate the effect of different carbon to nitrogen ratios and its method for rearing common carp (Cyprinus carpio) in the biofloc system through immunological parameters. A total of 750 fish species with a mean weight of 17 ± 0.5 g were selected and randomly divided into 30 fiberglass tank with a volume of approximately 250 liters of water. The treatments included three levels of carbon to nitrogen with different levels of 15, 20 and 25 with three levels of dietary protein including 25%, 30%, and 35% by three replications during the 56-day period of trial. Also, a control group was fed with 35% dietary protein in usual system with water exchange. Based on the results, The amount of total protein, albumin, and globulin showed significantly a numerical increase with increasing the percentage of dietary protein in biofloc treatments compared to the control treatment (P<0.05). Also, the lowest serum total protein and albumin were observed in the control treatment. Furthermore, the lowest serum bactericidal activity, lysozyme, and total complement (ACH50) were in control treatment that significantly different from the biofloc treatment with 30% protein and the ratio of C/N 15 (p<0.05). As a result, using the optimal ratio of carbon to nitrogen 15 with 30% protein due to the activity of lysozyme and complement is a good strategy for the production of common carp juveniles at the early stage in this system.

The main objectives of the present study were to estimate of catch age structure ، biomass and maximum sustainable yield of common kilka in Iranian waters of the Caspian Sea. The result shown that catch of kilka in Iranian coastal in 2018 decreased from 26153 ton to 24586 ton in 2019. The mean length was 104.3±10.6 at the same time and the minimum and maximum fork lengths were 52.5 and 137.5 mm and always fishes with 3 and 4 year olds had the highest frequency 78.1 and 80.6 percent respectively. The biomass of common kilka was estimated 76922.9 and 74342.7 ton, respectively. In these years, fish of the 3 year of this fish had the highest amount of reserves (respectively 24677.6 and 24254.8 ton) and the lowest reserves for 6-year-old fish, respectively. The breeders biomass of this species is 39557.4 and 36939.4 tons respectively and the ratio of biomass of broodstocks to the whole was 51.4 and 49.6 percent respectively. Acceptable Biological Catch was estimated 19500 tons , with a very cautious approach. The fishing mortality was more than reference points of common kilka at F0.1 and F40% (0.92 and 0.80) , In fact overfishing has occurred . Proper exploiting leads to continuous harvest and long-term stability of storage.

In recent decades, the growth of the aquaculture industry and the use of intensive culture methods has increased the susceptibility to pathogens in aquatic animals.Therefore, many researchers have focused on the stimulation of the immune system against pathogens.The use of common methods in the control of aquatic diseases has limitations duo to the some side effects. Antibiotics cause the increase of bacterial resistance, accumulation in muscle, environmental damage and another methods, such as vaccines, are costly.Medicinal plants, as a safe and inexpensive source, can be a suitable alternative to antibiotics, chemicals and vaccines with minimal side effects. So far, more than 250 medical plant species from 75 families and 32 orders have been reported mainly belonging to Lamiales, Fabals, Asterales, Malpighiales, Euphorbiaceae and Phyllanthaceae. There are the various biological activities in herbs due to the presence of bioactive compounds such as alkaloids, flavonoids, pigments, phenols, terpenoids, lectin, steroids and essential oils. The evaluation of these bioactive compounds have shown that they can be improved the immune system and antimicrobial defense in aquatic animals. A better understanding of the bioactive compounds function can be lead to the effective application of medicinal plants in aquaculture, as they can be used specifically for each fish species. The aim of the present work is to investigate the role of medicinal plants in stimulation of immune system and to study the properties of the antibacterial, antiviral, antifungal and antiparasitic effects in aquaculture.

Antioxidant are the main agents of neutralizing free radicals, which are active and harmful substances for humans The aim of this study was to investigate the antioxidant properties of aqueous extract of Sargassum vulgare brown algae collected from the shores of qeshm on a laboratory scale.

After collecting the algae from the shores of Qeshm and washing with fresh water extraction of Sargassum vulgare algae was performed then the desired extract was obtained in dry freeze dryer as a powder. the parameters of total Phenol, total antioxidant properties, free radical scavenging activity of DPPH, superoxide free radical, iron ion chelating ability and hyd roxyl radical were investigated in this study

According to the results the content of total phenol, total antioxidant activity, DPPH free radical, superoxide free radical percentage, iron ion chelating ability and hydroxyl radical in their highest concentrations equivalent to 16/22 mg of gallic acid per 100g of extract 521/70 mg of ascorbic acid per gram of extract, %24/08, %14/08 and %33/65 was calculated

Due to the high ability of Sargassum vulgare brown algae extract in antioxidant activities this algae extract can be introduced as a rich source of natural antioxidant compounds in food pharmceutical cosmetic and health industries

The aim of this study was to evaluate the health of Kabudal and Shirabad Streams and Zarrin Gol River in Golestan Province using biological indices (benthic invertebrate community). Aquatic invertebrates are one of the most important and beneficial organisms in biological monitoring. In this study, based on the existing barriers and the possibility of access to the river, 5 stations in Kaboudwal Stream, 3 stations in Shirabad Stream and 10 stations in Zarrin Gol River were determined. In order to sample large benthic invertebrates using a surber sampler with dimensions of 30.5 30 30.5 cm and with 3 replications in each station seasonally in a period of one year (2018-2019) were collected and identified based on reliable identification keys. Then alpha, beta and multivariate biodiversity indices of water quality health assessment were studied. The results of this study showed that the effluent of fish farms had a significant effect on river water quality so that the percentage of pollution-sensitive families in the stations after fish farms decreased and increased the frequency of resistant families. The streams of Golestan province generally experience moderate ecological conditions and move towards poor conditions, which with the increasing trend of destruction of ecosystems along riparian zone and the impact of agricultural and aquaculture activities, it seems that we will have these conditions in the future.

microalgae produce a wide range of protective compounds and pigments (mycosporid-like amino acids, Scytonemines, phycobiliproteins, and carotenoids) against ultraviolet (UV) radiation, which specially reduce the risk of skin cancer and aging. To compare the effect of solvents on UV protection factor (SPF) as well as the extacted amounts of carbohydrates, proteins and phycobiliproteins of Spirulina platensis different solvents including aqueous, ethanolic, methanolic, aqueous/ethanolic and aqueous /methanol were used. The yield of lyophilized extracts was compared. The results showed that ethanolic extract had a higher protective factor than other extracts (SPF=11.94 ± 0.00) also, this extract showed a higher amount of carbohydrates (2.39 ± 0.002 mg/ml) than other extracts. Aqueous extract had the highest amount of phycobiliproteins and extraction efficiency between other lyophilized extracts (90.05%). Inconclusion, due to the significant amount of SPF of ethanolic extract, the useage of this extract in sunscreen formulations as a natural UV filter coulb be suggested.

Small plastic particles are known as emerging pollutants and this has led to the development of studies in this field. Todays, many studies have examined the effects of microplastics on living organisms and aquatic organisms, but fewer studies have been conducted on the effects of nanoplastic on organisms; However, there is still no comprehensive information on the effects of these substances on living organisms and humans. The aim of this study was to investigate the hematological and biochemical responses of common carp in exposure to polystyrene nanoplastic. 84 common carp with an average weight of 30±5.1 were distributed in 4 food treatments (control with basic food and without nanoplastic, treatments containing 0.1, 0.5 and 1 ml of nanoplastic sprayed emulsion styrene on diet for 28 days. At the end of the experimental period, serum samples were collected to investigate some biochemical and hematological indices. Different concentrations of nano polystyrene plastic despite the increasing trend, red blood cell count, hemoglobin, hematocrit, MCV, MCH, MCHC, lymphocyte count, neutrophil, monocyte, basophil and eosinophil and serum biochemical indices, such as albumin, albumin. Serum had no significant effect (P> 0.05), but the level of white blood cells and glucose at a concentration of 1 ml (highest concentration) was significantly higher than the control group (P <0.05). Finally, higher concentrations of polystyrene nanoplastic are likely to increase stress and inflammatory responses in common carp.